The size and utility of any chain is dependent on the type and size of the links in the chain. Large roller-type links are often 2-8 inches in length and may be 12 inches or more in length. In industrial conveyor systems, for example, large roller-type links are commonly used to form heavy duty roller chains that drive conveyor systems. Problems arise in industrial conveyor systems when any link in the conveyor chain is damaged or broken. Removing the entire chain from an industrial conveyor system in order to replace a weakened link is difficult, time consuming and expensive. Thus, it is preferable to remove and replace any link in the conveyor chain while the chain remains in place on the conveyor system rather than removing the chain from the conveyor system and using a workbench to repair the chain.
The problem of removing or replacing a link in a chain, especially in place removal of links in large roller chains, is well-known and has been described in detail in, for example, U.S. Pat. No. 2,895,289 (Wognum). Prior art tools generally provide an apparatus to cradle the chain such that the cradle integrates the mechanism for removing or replacing the links with adequate backing to counter the force required to remove the link pins. Unfortunately, the prior art tools sometimes are inadequate when large roller chains need to be repaired because of the large size of the tool required and the absence of space in which to position such a large tool when the chain is in place in with industrial equipment, for example.
For the large roller chains used in industrial conveyors, the traditional method of in-place removal of the link pins is with a shank and a hammer. Typically, the end of the shank is positioned on the end of a link pin and the hammer is used to strike the shank, forcing the link pin out of the link. The pins are usually removed one at a time. The amount of force required to free the pins is great and using a hammer to apply such force is dangerous and imprecise. The lack of control of the force frequently causes the weakened link to fracture unexpectedly or the pins to suddenly pop out, endangering the worker.
An objective of the present invention is the safe removal and replacement of link pins and links in large roller chains while the chain remains in place.
Another objective of the present invention is to provide a tool that can be used in a limited amount of space despite the large size of a chain link.
A further objective of the present invention is to provide a tool that can be used manually or with power tools and is adaptable for chains of varying widths.